monoclonal, HIV, vac

• • monoclonal antibody = single type of antibody that can be isolated + cloned
  • antibody = proteins which have a binding site complementary in shape to certain antigens
• Direct monoclonal antibody treatment:

  treating cancer = creating antibodies with complementary binding sites to antigen on outside of cancer cells

  • antibodies travel around body and attach to cancer cells preventing chemical binding to cancer cells

  reduce uncontrolled cell division preventing them growing and designed to only attach to cancer cells not normal cells
• indirect monoclonal antibody therapy:

  treating cancer = creating antibodies with complementary binding sites to antigen on outside of cancer cells with drugs attached to them

  • cancer drugs = delivered directly to cancer cells and kill them

  reduce harmful side effects of traditional chemotherapy and radiotherapy
• monoclonal antibodies can be used for:

  • medical treatment (cancer)
  • medical diagnosis (influenza, chlamydia, covid-19)
  • pregnancy test (detect hormone hCG)
• ELISA TEST: pregnancy test

  • first mobile hCG antibody complementary to antigen/ hCG being tested for
  • second immobilised hCG antibodies, fixed in position on the test strip bind to the hormone that is already attached to the mobile hCG antibody and the blue bead. This causes the strip to turn blue, only if the hormone is present
  • third antibody is immobilised and complementary in shape to first antibody

  
• Indirect ELISA test:

  1. add test sample/ blood sample from patient to base of beaker and wash to remove any unbound test sample
  2. add antibody complementary in shape to antigen you are testing the presence of + wash to remove any unbound antibody
  3. add second antibody that is complementary to shape of first antibody + binds. Second antibody has enzyme attached to it
  4. substrate for enzyme which is colourless is added; if enzyme is present coloured product produced to indicate presence of antigen

  intensity of coloured product = quantity of antigen and therefore enzyme

  
• ethical issues of monoclonal antibody: requires mice to produce antibodies + tumour cells = is animal life justifiable to enable better treatment of cancers and detect diseases

  
• passive immunity is when antibodies are introduced into the body - pathogen doesn't enter the body so plasma cells and memory cells are not made

  • no long term immunity
• active immunity is when immunity is created by its own immune system following exposure to pathogen
• 2 types of active immunity:

  • natural immunity = following infection and creation of own antibodies and memory cells
  • artificial immunity = introduction of a weakened version of the pathogen or antigens via a vaccine
• vaccines are a small amount of weakened or dead pathogen/ antigens are introduced in the mouth or by injection
• process of vaccines:

  1. exposure to the antigen on weakened or dead pathogen activates B-cell to go through clonal expansion + differentiation (clonal selection)
  2. B-cells undergo mitosis to make large number of cells, these differentiate into plasma cells or memory B cells
• memory cells can divide rapidly into plasma cells when re-infected

  • they can live for decades
  • divide by mitosis rapidly before symptoms can occur
• Herd immunity is when enough of the population are vaccinated the pathogen cannot easily spread amongst the population

  allows protection to those not vaccinated (ill, too young etc)
• antigen variability is when...

  • a pathogens DNA mutate frequently which then results in the shape of antigen changing
  • any previous immunity will no longer be effective
  • the memory cells will only have memory of old antigen shape not new one